With 13 Oscar nominations, filmmaker Guillermo del Toro’s “The Shape of Water” defies categorization. Part fantasy, part science fiction, part dreamy romance, it depicts the love story between a fish-man captured by government scientists and the quiet, reclusive woman who helps set him free.

A frequent del Toro collaborator, Doug Jones plays the aforementioned fish-man and said the closest he had come previously to “playing a love interest in a monster suit” was in “Hellboy II: The Golden Army.”

“I was Abe Sapien — the fish-man in that too — and I had a love interest and we had a flirtatious back and forth but it never got to fruition, as is typical for monster movies.”

When del Toro approached him about “The Shape of Water,” Jones said the director explained that he would be playing “this romantic interest that becomes involved in a consummated relationship. And he said to me, ‘I know you’re a good Catholic boy, so I want to make sure this is going to be OK with you.’ And I was like (voice rises an octave), ‘Oh, hahaha, how far do we go?’ And he said, ‘Well, there’s a bathtub involved.’ And I thought, ‘Oh, for dear sakes. How about you start at the beginning and just tell me the whole story and get me to the bathtub and then I’ll tell you how I feel about it!’ Because he didn’t even have a script yet; this was in 2014 when he was telling me about this, we were working on ‘Crimson Peak’ together, I was two of his ghost ladies in that.”

So del Toro walked Jones through the story. “And I’m mesmerized, I’ve got my chin in my hands: ‘So then what happens? Oh really? Aw!’ And of course we end up in her apartment and the bathtub and of course, where else are you going to put a fish-man? And I was like, ‘Ah, we’re at the tub, I get it now. And there’s no wall between us, no supervision, no chain involved, we have free access to each other — awwww, of course there’s love!’ So I told Guillermo, ‘I think the good Catholic boy in me is OK with it because there’s an innocence to it and a charm to it and I don’t even think the Bible itself has a protocol for animals in the wild getting married before they have sex (laughs), so I think it’s going to be OK!’”

Jones has made transforming himself something of a specialty and he has extensive experience with monster suits and other elaborate prostheses. Which means there are all kinds of perils that could lead to a worst moment — including his costume for “The Shape of Water,” which encased him head-to-toe in rubber, with just a single flap that “could come unsnapped” in the front if he needed to use the bathroom.

“But I didn’t have easy access to the flap,” he said, “because I was wearing webbed fingers with claws on them and those were glued onto the arm. It was a huge production to go to the bathroom — so I decided it would be better not to!” Luckily, there were no mishaps.

The same can’t be said for his co-star on a much earlier film. “I have a story for you,” Jones said, “and it’s from a movie from 1998 that went straight to video called ‘Bug Buster.’”

My worst moment …

“Oh gosh. OK, this is going to sound preposterous because it was: The movie is about a bunch of insects that are infesting this town and people are dying from their bites, so they call in this general from some branch of the military who is now a specialist in eradicating problems. He’s played by Randy Quaid and he comes to this town decorated with all kinds of military hardware and wearing Coke bottle glasses. Hilarious. And he’s like, ‘We’re going to kick some bug (butt)!’ I think the movie was supposed to be scary? But it’s one of those movies that you laugh at because it’s just so bad.

“So Randy’s on the case and he ends up following the trail to this cave that’s just outside of town and he ends up in there all by himself with some kind of weaponry, ready to take on this bug infestation — and he sees a 6-foot-5 mother bug played by, yes, Doug Jones! (Laughs) I am very proud to have on my resume Mother Bug, if you must know.

“So I turn around and see him when he yells at me, and I’m guarding my pile of eggs because the infestation must continue — that’s my purpose! — so he pulls out a rifle and pelts me with bullets but they don’t do anything. Then he pulls out a CO2 gun to freeze me, and nothing. Then he pulls out a flamethrower and I don’t burn. So he throws everything down and puts up his fists — this is where it gets weird — he puts up his fists and says, ‘All right: you and me, mano a mano!’ Like we’re going to have a hand-to-hand fistfight, right? It’s utterly absurd.

“And I am in this costume that is incredibly difficult to maneuver in. The further you get away from human, the harder the costume is to wear because of the posture you have to hold, especially a six-legged insect with a stinger coming out of your butt and a head that’s way up above your own. My actual face was in the neck of this insect behind some netting. So I’m itchy and I’m in a little bit of my own hell in this costume, kind of bent over to make sure that all six of my legs touch the ground every so often. But my two front arms — my real arms — were operating these pincers. It’s an insect, she must have pincers on the front. It was a cockroach-y type of insect.

“The long pincers were made of fiberglass, so here’s the discussion I had with Randy, who can barely see my face through this netting: ‘Randy, listen: I can’t see you very well so please be careful.’ And he says, ‘Doug, it’s OK, buddy, I’ll be fine! Do what you gotta do, we’ll get through this!’ So, no worries in the world. Great.

“We have a hand-held camera following us for the entire fight scene and the swinging starts, the body-shoving, the banging into the walls of the cave, rolling around on the ground. And I felt myself connect with him a couple times with my arms, my pincers. And we end up with him on his back and me on top and they call ‘cut.’ A team of people have to help me get up so I can go back to my special bug chair that I lean forward on because I’ve got a stinger in my butt. So I’m breathing heavy because that was a lot to do in a heavy bug suit and I ask one of the makeup creature effects people, ‘Can you go check up on Randy? I didn’t see him get up.’

“So she walks over, I can’t see anything and I hear this voice from across the cave, it’s Randy, and he says, ‘Doug buddy, can you hear me? I’m fine, don’t worry about a thing, we can do it again! It’s all good, it’s all good — don’t worry about a thing!’ All right, I guess he’s fine.

“And the next voice I hear was a young production assistant, like this 20-year-old kid, and he says, ‘Um, can I get some ice over here? I can’t stop the bleeding.’

“Well, I had gashed both — both — of Randy Quaid’s forearms! The blood was gushing out of this man and how he had the wherewithal to say, ‘I’m fine! Let’s do it again!’ — are you kidding me?

“So he comes back for Take 2 with these flesh-colored bandages on, but it didn’t match at all but it was ‘Bug Buster’ so it didn’t matter.”

What was going through his mind …

“All that went through my mind the rest of the day was, ‘I’m going to kill Randy Quaid and this is how I will be remembered — the guy who killed Randy Quaid.’ We did have a quick discussion before Take 2 and we decided that instead of me swinging my arms toward him, he would grab the top of my arm and guide that swing. He figured out a way to keep my pincers from connecting with him.”

What were things like with Quaid afterwards?

“I was like, ‘So sorry!’ And he was like, ‘No, it’s fine, it’ll be great!’

“A few years later I played an FBI agent that got turned into a carrot — now that’s a long story — for ‘The Adventures of Rocky and Bullwinkle’ (from 2000) and Randy Quaid was playing the head of the FBI in that movie. We didn’t actually have any scenes together.

“But we were all at the table read, where we sit down in a conference room and read the script out loud. So there was Randy Quaid playing the head of the FBI and I rounded the table before we started and said, ‘Randy, hi — you’re not going to recognize me. (Laughs) I’m Doug Jones and I played the Mother Bug in “Bug Buster”’ and he’s like, ‘Oh my gosh! That was somethin’, wasn’t it?’ And I said, ‘Yes it was! I’m glad to see you’re standing and alive because I thought I almost killed you that day.’ And he said, ‘Really, why?’

“He didn’t remember the incident at all. So I could have let it go! If I had bled all over a cave, I think I would have remembered that. But Randy was like, ‘Really? Oh, well. Thanks for saying so, but no, I’m good!’ So we had a lovely little reunion years later and I guess all was forgiven because he forgot about it!”

The takeaway …

“What I learned that day was to rehearse a fight scene in costume before you do it, because so much can go wrong. And from watching Randy Quaid’s work ethic I thought, ‘Well, there’s a trouper.’ The show must go on, that’s an old saying in showbiz, and Randy Quaid was living proof of that. When you see the end product you realize we weren’t making art, but in the moment I loved his work ethic and I learned a lot from that.”